physics

gamma radiation and medicine

atoms emitting gamma radiation are decaying a lot so doctors have to produce their own radioisotope
they use a linear accelerator to smash neutrons into nucleus' which are already stable, the neutrons are absorbed and form radioisotopes
sterilisation makes equipment safe to use
gamma rays can kill cancer using a gamma knife, however this is a complex process and doctors must ensure the tumour recieves a high dose whilst limitng the damage to the surrounding healthy tissue, thus a wide beam of low intesity gamma rays are focused onto the tumour
radioactive metal tracers are used to help diagnose problems without operating
a sample is injected or eaten by patient so they can see an image of the internal organs, the gamma radiation is used as it is penetrating although the source must have a very short half life so it does not stay radioactive for long in the body
when the radioactive tracer is consumed doctors have to wait for it to travel around the body, if there is a blockage or tear special cameras can detect the radiation emitted from this area will be different

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inside a nuclear power station the heat from a nuclear reaction is used to turn water into steam, this travels along pipes to a turbine which is made to spin by passing steam, the tubine is connected to a generator which spins and makes electricity
nuclear fission is the splitting of atoms which is the nuclear reaction in a power station
nuclear reactors can be used to power some submarines and aircrafts
to split an atom in nuclear fission a nucleus must absorb an extra neutron this makes it split, it then splits into two smaller nuclei, this releases the energy to power nuclear reactors
production of radioactive waste from fission and from reactor materials means that it is very expensive to dismantle a nuclear power plant, this process is called decommissioning and it takes decades

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splitting a single atom does not release very much energy so a large number of nuclear fissions are needed
in fission two or three neutrons are emitted, they can go on to hit more atoms which release even more neutrons and the cycle continues
in a nuclear reactor the fission is controlled, in nuclear weapons it is not
special rods called control rods are raised and lowered into the reactor, they are made of a material that absorbs neutrons reducing the number available

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in nuclear fusion two small nuclei of hyrdrogen are fused together which makes helium
nuclear fusion provides the energy from the sun and also hydrogen bombs
it is very hard to sustain nuclear fusion on earth as the atoms are positively charged and they repel each other, in the sun it can be achieved as the core is hot and under high pressure so they move about and have to smash into each other
nuclear fusion to generate electricity would produce no carbon dioxide, a alot of elecricity and no radioactive waste
controlling the condition for fusion is bery difficult and expensive, however some scientists said they could cause a cold fusion, nobody could re create the findings which lead scientists to believe the data was false
when hydrogen bombs explode a uncontrollable chain reaction releases vast amounts of heat, this causes the hydogens to fuse and release even more energy

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